Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 460.89
Broken: version: 2.93.0 Alpha, branch: master, commit date: 2021-02-21 00:52, hash: rB4dd782a1a395
Short description of error
In the 3D view you have a red border around an active render border. In the Image editor not.
This can lead to hours of lost render times since you cannot see if a render border is active or not. And is inconsistent. Two equal functionalities should work equal.
Exact steps for others to reproduce the error
Open Blender, activate Render border in the 3D view and render a portion with viewport shading rendered.
Now render the image, and render a portion of the image with enabled render border. You will notice that in the 3D view you have a red rectangle that indicates that the render border is active and what area to render.
But in the image editor you just see that just a portion is rendered. The next render can be with or without render border. There is no visual hint if the tool is active or not. And no hint if you have selected the correct area for preview rendering.